The invention relates to an improved tunnel oven-broiler of the humpback type wherein food products are heated by infrared radiation as they are conveyed through a tunnel-form cooking chamber.
It is expected in restaurant, industrial and institutional cooking that greasy foods, and particularly meat products such as hamburgers, steaks, chops, etc., will tend to flare up and char as grease rendered by the food catches on fire, as will occur when exposed to temperatures sufficient for broiling, for example. This is particularly so for beef, pork, and lamb, but also occurs with fowl, including chicken, turkey, and duck.
Either limiting or avoiding such flaming or flaring up of greasy foods can be extremely difficult since meat grease, for example, may begin vaporizing at only about 150.degree. F. Therefore, the exposure of grease vapors to the ordinary atmosphere at even the modest temperatures present in ovens and broilers is likely to produce combustion.
If such flaring or flaming of meat and grease in an oven of the present character is not controlled, there is difficulty, if not impossibility, of accurately maintaining temperature control. This is because the flames and flaring up cause improper response by temperature sensing elements not indicative of the true temperature in the oven.
In recent years, tunnel ovens have been developed for use in the fast food and industrial cooking field, such as disclosed in Wells U.S. Pat. No. 4,008,996. Ovens of this type cook by infrared emission from internal services of the tunnel-form cooking chamber. Such tunnel ovens have provided a revolutionary way of cooking which preserves the taste, succulence and moisture of food products. They do not utilize heated air for cooking, which tends to dry out food.
In the genesis of ovens of the present type, it has been proposed, as in Wells et al U.S. Pat. No. 4,366,177, to provide a method of substantially flameless broiling in an oven of the type which has come to be known as having a humpback configuration. In a humpback oven, the cooking chamber is configured so that the opening and exit to the tunnel-formed chamber is positioned lower than the floor of the chamber for entrapping a heated, oxygen-starved atmosphere. The food products are conveyed up an inclined path into such atmosphere where they are heated to temperatures at which they otherwise would flame but, because of the denial of oxygen, may cook or be broiled in a substantially flameless manner. The cooked food products are moved continuously through such atmosphere and are delivered by being conveyed down an inclinded path.
Unexpectedly, a problem was discovered in such cooking arrangement, in that the cooking, when carried out in a totally flameless manner within a totally entrapped oxygen-starved atmosphere, tended over a period of time to build up in the entrapped atmosphere grease vapors and smoky constituents of the broiling process. As a consequence, the introduction of cold, uncooked articles of meat entering the oven was found to result in condensation on the cold meat surfaces of grease vapor and smoky products of the broiling process, imparting an undesirable taste to the cooked product.
Because of these problems, the present invention previously has proposed to permit a certain amount of slight but tightly controlled grease combustion to occur in the humpback-configuration oven-broiler in order to permit conversion or oxidizing reaction with the vapor or smoke constituents within the oven atmosphere to prevent such products from being deposited on the meat.
Additionally, the inventor has discovered that there is a continuing demand by restaurant customers for what is termed "char-broiled" meat products, which is to say, meat products broiled with at least some impringement of flame upon the product to impart a slightly carbonized taste like that resulting from broiling over an open charcoal fire upon which the dripping of grease over an open charcoal fire upon which the dripping of grease as it is rendered from the product will drip and flare up, causing flames to lick at the meat.
Accordingly, when one seeks to make commercially-successful use of a tunnel oven of the present type, one is confronted with the need to provide an oven which allows the user to achieve a delicate balance of maintaining, on the one hand, rather high broiling temperatures which are relatively precisely maintained with, on the other hand, permitting a small amount of grease from the meat products to be burned so that a slight flame impingement for sizzling of the meat with what amounts to combustion of the grease can occur. At the same time, the oven must not permit the undesirable above-noted accumulation within the oven atmosphere of smoky combustion products and grease vapor which, together with moisture emanating from the cooked meat product, produces a vapor-saturated oven atmosphere which would condense upon the meat products and leave an undesirable bitter taste.
Accordingly, it is an object of the present invention to provide an improved oven or so-called oven-broiler of the humpback type which permits broiling of meat products to be carried out in a relatively quiescent, substantially trapped atmosphere but wherein there is not permitted uncontrolled burning or flaring up of meat and wherein a small and unobjectionable degree of flame impingement is permitted, if desired.
It is similarly an object of the invention to provide such an oven-broiler wherein the grease and moisture vapors within the cooking atmosphere are condensed out and permitted to drain from the oven tunnel or chamber before they can become deposited upon the meat product.
Another object of the invention is to provide an oven-broiler wherein there is a controlled interchange of the atmosphere within the cooking tunnel with that exteriorly of the chamber while maintaining a trapped, somewhat oxygen-starved atmosphere within the tunnel.
An object of the present invention is also to provide an oven-broiler of the character stated wherein certain novel effects can be achieved such as, for example, the introduction of smoking or flavoring elements (such as through the use of wood chips or the like) into the cooking tunnel during cooking.
A further object of the invention is the provision of such an oven-broiler which permits relatively precise and effective control over the communication between the atmosphere in the cooking chamber and that exteriorly of it; which permits rapid reconfiguration of the oven structure for such purposes; which is rapidly and easily cleaned as by the use of a self-cleaning cycle; and from which the oven components may be rapidly removed for their separate cleaning.
An object of the present invention additionally is to provide such a tunnel oven-broiler in which greasy food products such as steaks and chops may be rapidly and effectively cooked at the relatively high temperatures especially desirable for broiling but without concern for the steaks or chops being excessively burned or undesirably exposed to the excessive impingement of flame; and in which such food products can be continuously supplied to and delivered from the cooking tunnel at relatively high volumes and rates while the tunnel entrance and exit openings remain open.
It is an object of the present invention to provide such a tunnel oven-broiler which avoids loss of temperature control within the tunnel during cooking which otherwise could result from flaming and flaring, and in which the oven temperatures can be maintained sufficiently precisely and accurately to provide an even, complete and consistent cooking of the food product.
A further object of the present invention is to provide such an oven-broiler which by its humpback configuration avoids wasteful escape of thermal energy and with consequent increase of efficiency.
Another object of the invention is to provide an oven-broiler of such configuration which allows relatively less skilled personnel to carry out broiling of food products more precisely and to a greater degree of uniformity of result than has been possible with other types of ovens.
It is additionally an object of the present invention to provide such a tunnel oven-broiler which can be relatively economically and simply manufactured, and which is reliable and of extremely durable, long-lasting configuration, as well as being well suited for heavyduty volume commercial usage.
Briefly, the invention is concerned with an oven-broiler of the humpback type including a tunnel-form cooking chamber and a conveyor extending through it for conveying food products through the chamber for cooking of the products by emission of infrared radition from the walls of the tunnel. The oven-broiler includes structure defining an entrance and an exit at opposite ends of the chamber for ingress and egress of the food products. The entrance and exit are each located at a level lower than the chamber for causing the chamber to entrap a heated, oxygen-starved atmosphere in which flaming of the food products cannot freely occur. In accordance with the invention, the oven structure is configured to define an elongate aperture extending along the bottom of the chamber for providing communication between the chamber and the external atmosphere. Control means is provided being associated with the aperture, for controlling the nature of the oven chamber atmosphere by controlling the communication through the aperture, and such means preferrably takes the form of one of several types of bodies including a control surface positioned within the aperture below the conveyor for contact with grease or other liquids produced by cooking of the food products.
Other objects and features will be in part apparent and in part pointed out in the following description.